“Every day, I ride this train into work, so this is a kind of goodbye,” Ms. Martínez said.
The antique Belgian-built cars, a symbol of Buenos Aires’s early-20th-century wealth, were taken out of service this year, and their retirement is a poignant example of the city’s struggle to preserve its physical history as some of its icons and infrastructure crumble.
An audit last fall cautioned that much of Buenos Aires’s underground transit system was in a dangerous state of disrepair, and that the city’s oldest line — linking the presidential mansion, the Casa Rosada, and the Constitución regional train station — should be removed from service immediately.
 “Maintenance is not considered adequate,” the audit said, citing a train disaster in Buenos Aires last year that killed 49 passengers and wounded hundreds more.
But a local reaction against the retirement of the La Brugeoise trains, known here affectionately as Las Brujas, or the witches, has fueled a debate over which elements of Argentina’s rich cultural heritage are worth saving.
“They want to modernize and expand, but they haven’t considered how the trains move people emotionally,” said Gerardo Gómez Coronado, who oversees architectural protection at the city’s planning department.
Preservationists say illegal demolitions, chronic underinvestment and unimaginative architecture that is replacing the historic buildings threaten to erase the city’s heritage as a mecca for European immigrants, who arrived in boatloads to what was, at the beginning of the last century, one of the richest countries in the world.
“Argentina promised to be a very, very important country,” said Teresa Anchorena, an artist and member of the National Commission of Museums, Monuments and Historic Places, which lobbies for the protection of hundreds of sites throughout the country. “Argentina’s broken promise is reflected in its buildings.”
With its ornate cars, the Buenos Aires subway was the first built in Latin America and the 13th in the world, ahead of the systems in Madrid, Tokyo and Moscow. At the time, Argentina was the world’s ninth-richest country, according to the historic incomes database of the British economist Angus Maddison.
In 1910, newspapers in 80 languages were available in Buenos Aires. The city had the region’s biggest zoo and a well-regarded research center on infectious diseases. Argentina’s gross domestic product per capita was nearly twice that of Spain’s and nearly five times bigger than Brazil’s, according to the database.
Decades of fighting seized lands from the indigenous Patagonians and greatly expanded Argentina’s agricultural opportunities in the country’s south. The ensuing economic bonanza fueled by beef and grain exports, which continue to be core industries here, drew millions of immigrants from Europe.
The most successful among them flaunted their good fortune by commissioning famous European architects. Immigrants financed opera houses modeled after those in Vienna and Paris, the world’s biggest Edwardian train terminal, and a private mansion that was a tribute to the French palaces of Louis XIV and is now the French Embassy.
Many buildings, including the Palacio Anchorena, built by Ms. Anchorena’s mercantilist grandfather, who was prominent during Argentina’s gilded age, are protected by law from demolition along streets like Alvear Avenue, a prime example of Argentina’s belle epoque.
But in many neighborhoods, city code has been flouted, and historic buildings have been demolished at astonishing speed since Argentina’s economic collapse in 2001, when the country defaulted on nearly $100 billion in sovereign debt, plunging half of the population below the poverty line.
Government leaders justify a laissez-faire attitude toward new construction by framing it in terms of economic recovery, Mr. Gómez Coronado said.
(Chasity M.)